1. Field of the Invention
The invention relates to a machine for the manufacture of an at least single-face corrugated board web comprising two fluted rolls for producing a corrugation on a paper web, a gluing device for applying glue to the peaks of the corrugation of the corrugated paper web, a pressing device for pressing a liner web on the glued peaks of the corrugated paper web, which rests on one of the fluted rolls along a pressing zone, the pressing device having an endless pressing belt, which is guided via a deflection pulley and a further pulley and which is pressed against the fluted roll along the pressing zone, and the pressing device having a tensioning device for the pressing belt.
2. Background Art
A machine of the generic type is known from EP 0 492 310 A1. The webs of corrugated board made by machines of this type have a width in the range of between 1.2 and 2.8 m, usually 2.5 m. However, because the deflection pulley tends to bend, there are considerable difficulties in obtaining uniform pressing by the belt over the entire width of the paper web. Therefore, EP 0 492 310 A1 provides for a crowned design of the deflection pulley so as to compensate for the bending of the deflection pulley. The requirements are considerable. In addition, the pressing belt is subject to torsional effects. Further, it is extraordinarily time-consuming and expensive to replace a damaged belt. At least one deflection pulley is supported in bearings, which are each slidable by means of a tensioning drive formed by a piston-cylinder drive.
EP 0 104 372 B1 teaches having a belt pressed against the corrugated roll in the zone of pressing by means of a pad of compressed air.
It is known from U.S. Pat. No. 2,638,962 to guide an endless pressing belt via two deflection pulleys, which are lodged in a link-type frame. The pressure exercised can be modified by adjusting this link-type frame.
It is known from EP 0 024 817 B1, in the zone of pressing, to press an endless belt from its inside against the fluted roll by means of a pressing element.
DE 38 31 924 A1 teaches a roll, in particular a counter-pressure roll of a pair of rolls for the conveyance and/or processing of a web of material to have a stationary roll support and a movable roll sleeve. At least one roll pipe enclosing the roll support is disposed between the roll support and the roll sleeve. This roll pipe is articulated to the roll support for defined motion. The roll sleeve is rotatably supported on it. This design ensures that the counter-pressure roll no longer needs any external pivot levers.